1. Field of Invention
The present invention relates to a pneumatic tool and, more particularly, to a pneumatic tool equipped with a direction switch operable with a single hand.
2. Related Prior Art
Disclosed in Taiwanese Patent Publication No. 387316 is a pneumatic tool 1 equipped with a direction switch operable with a single hand. The pneumatic tool 1 includes a handle 11 on which an upper control member 2 and a lower control member 3 are installed. The upper control member 2 is operable to cause the pneumatic tool 1 to rotateor stop. The lower control member 3 is operable to cause the pneumatic tool 1 to rotate in a direction or in an opposite direction. A user operates the pneumatic tool 1 with a single hand. The user holds the handle 11 and the lower control member 2 with the thumb, the middle finger, the ring finger and the little finger. The user presses the lower control member 2 with the middle finger, the ring finger and the little finger in order to cause the pneumatic tool 1 to rotate. The user operates the upper control member 3 with the index finger.
However, there are problems with this conventional pneumatic tool 1. Firstly, the user soon has fatigue in the hand, pressing the lower control member 2 with the middle finger, the ring finger and the little finger while keeping the index finger off the upper control member 3. The user might get hurt in the hand if using this pneumatic tool 1 for long. Moreover, the user cannot hold the pneumatic tool 1 steady with the middle finger, the ring finger and the little finger. Furthermore, the user may unintentionally press the upper control member 3 with the index finger and change the direction of the rotation of the pneumatic tool 1, and this could be dangerous.
Disclosed in Taiwan Patent Publication M275925 is a direction switch of a pneumatic tool. A space 16 is defined in a front side of a handle 15 of a piston-shaped body 10 of the pneumatic tool. The direction switch includes a block 20 for controlling air currents. The block 20 defines upper and lower intakes 21, upper and lower outlets 22 and two apertures 23. All of the intakes 21, the outlets 22 and the apertures 23 are horizontal. The block 20 defines four channels 24 that are vertical for communicating the apertures 23 with the intakes 21 and the outlets 22. Long rods 25 are positioned in the intakes 21. Short rods 25′ are positioned in the outlets 22. A user operates the pneumatic tool with a single hand. The user holds the handle 15 with the thumb, the ring finger and the little finger. The user presses an upper portion of a trigger 30 with the index finger in order to cause the pneumatic tool to rotate in a first direction, and alternatively presses a lower portion of the trigger 30 with the middle finger in order to cause the pneumatic tool to rotate in a second direction opposite to the first direction.
However, there are problems with this conventional direction switch. To cause the pneumatic tool to rotate in the first direction, the user keeps on pressing the upper portion of the trigger 30 with the index finger while keeping the middle finger off the lower portion of the trigger 30. To cause the pneumatic tool to rotate in the second direction, the user keeps on pressing the lower portion of the trigger 30 with the middle finger while keeping the index finger off the upper portion of the trigger 30. The user soon has fatigue in the hand. The user might get hurt in the hand if using this pneumatic tool for long. Moreover, the user cannot hold the pneumatic tool steady with the middle finger, the ring finger and the little finger. In addition, the user may unintentionally change the direction of the rotation of the pneumatic tool, and this could dangerous. Furthermore, the elements are numerous, and the direction switch is complicated. The assembly, the maintenance and the repair of the direction switch are difficult. Moreover, in operation, only one pair of the intake 21 and the outlet 22 is used while the other pair of the intake 21 and the outlet 22 is idle, and this is a waste.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in the prior art.